When joined components are expected to be exposed to relatively high temperatures, the options for joining the components are limited. Joining methods such as welding, brazing, active metal brazing and mechanical fastening can be utilized to join components for service in high temperature environments. However, these joining techniques can be difficult to implement, may not be universally applicable to all substrates and materials, and can be prone to brittle fracture. Joining techniques can become further limited when it is desired to join disparate materials, such as ceramic to silicon.
In some cases a binary or eutectic alloy, such as a gold/nickel eutectic braze, can be utilized as a bonding layer to couple the components together. Depending upon the particular composition, binary or eutectic alloys are relatively heat resistant. However, the use of a binary or eutectic alloy requires metal films (also known as bonding films, metal coatings or metallization) on the associated component(s) to allow the binary or eutectic alloys to adhere to the associated component and to block diffusion of undesired materials therethrough. Accordingly, there is a need for metal films that can be used in binary or eutectic alloy joining procedures that can adhere well to the associated component, resist significant diffusion therethrough and be thermodynamically stable at elevated temperatures. There is also a need for metal films which are robust and which are electrically conductive so that the films can serve as an electrical contact layer.